Why two classes PMLinearCongruentialRandomGenerator and PMCongruentialRandomNumberGenerator? #219

There are two classes that looks quite similar: PMLinearCongruentialRandomGenerator (subclass of Object) and PMCongruentialRandomNumberGenerator (subclass of PMPseudoRandomNumberGenerator). Apparently the first one is coming from DHB book, the origin of the second is unclear. We should find a way to combine them in one class in the PMCongruentialRandomNumberGenerator class hierarchy.

Same problem with PMMitchellMooreGenerator who is a subclass of Object and not PMPseudoRandomNumberGenerator.

Same problem with PMMarsagliaKissRandomKernel who is a subclass of Object and PMMarsagliaKissRandomKernel a subclass of PMPseudoRandomNumberGenerator.